부산대학교 도서관

In this study, cobalt-iron binary alloy microcolumns were prepared by micro-anode guided electroplating (MAGE) method, and their electrochemical characters for oxygen production in 1 M KOH were investigated. The advantage of microcolumns is that a three-dimensional electrode can be constructed in a minimal area, which offers effectively catalytic oxygen reduction to supersede the thin-film electrode. On the other hand, the synergistic effect among cobalt and iron is available for constructing a superior reactivity binary alloy in oxygen reduction. In MAGE, a glass tube is used to mount a platinum wire with a diameter of 250 μm, exposing the micro-anode with a bottom area of 0.0491 mm^2, and an enameled copper wire with a diameter of 0.643 mm^2 to expose its cross-section 0.325 mm^2 as the cathode. A bias was set at 3.6 V between the micro-anode and cathode, and the separation was fixed at 50 μm for electroplating. The electrolyte formulation is made from 0.30 M cobalt sulfate heptahydrate, 0.40 M boric acid, appropriate amount of ascorbic acid, 0.20 M sodium sulfate, and iron sulfate heptahydrate with varying concentrations of 0.15 M, 0.20 M, 0.25 M, and 0.30 M, which dissolved in deionized water. The surface morphology of microcolumns was examined through SEM, the chemical composition was analyzed by EDS, and the crystal structure was determined by XRD. Then, the alloy microcolumns were immersed in 1 M KOH for chronopotentiometry and linear sweep voltammetry tests to survey the electrochemical properties and oxygen evolution efficiency of the cobalt-iron alloy.